assignment5-planet-error1.js

var earth = [];
var moon = [];


function setup() {
  createCanvas(800, 500);
  background(0);
  for (var i = 0; i < 3; i++) {
    moon.push(new Particle(random(100, 200), random(150, 250), random(1, 3)));
    moon[i].vel.y = random(1, 2);
  }

  earth[0] = new Particle(random(width), random(height), random(5, 15)); // (x,y,mass)
  earth[0].vel.x = random(0, 0.1);

  earth[1] = new Particle(width / 2, height / 2, random(15, 30)); // (x,y,mass)
  earth[1].vel.x = random(0, 0.1);
}




function draw() {
  background(0);
  for (var a = 0; a < moon.length; a++) {
    for (var b = 0; b < moon.length; b++) {
      moon[a].applyAttraction(moon[b]);
    }
    moon[a].applyAttraction(earth[0]);
    //moon[a].applyAttraction(earth[1]);
    moon[a].update();
    moon[a].display();
  }
  for (var a = 0; a < moon.length; a++) {
    for (var b = 0; b < moon.length; b++) {
      moon[a].applyAttraction(moon[b]);
    }
    moon[a].applyAttraction(earth[0]);
    moon[a].applyAttraction(earth[1]);
    moon[a].update();
    moon[a].display();
  }


  earth[0].applyAttraction(earth[1]);

  earth[0].update();
  earth[0].display();
  //earth[1].update();
  earth[1].display();

}

"use strict";

class Particle {
  constructor(x, y, m) {
    this.pos = createVector(x, y);
    this.vel = createVector(0, 0);
    this.acc = createVector(0, 0);
    this.rad = 2;
    this.mass = m;
    //this.c=color(random(255),random(255),random(255))；
  }
  applyForce(f) {
    f.div(this.mass);
    this.acc.add(f);
  }
  applyAttraction(other) {
    var force = p5.Vector.sub(other.pos, this.pos);
    var distance = force.mag();
    force.normalize();
    force.mult((0.5 * this.mass * other.mass) / (distance * distance))
    this.acc.add(force);
  }
  update() {
    this.vel.add(this.acc); // vel = vel + acc;
    this.pos.add(this.vel); // pos = pos + vel;
    this.acc.mult(0); // acceleration has to be reset after being applied! ***
  }
  display() {

    push();
    translate(this.pos.x, this.pos.y);
    // beginShape();
    // curveVertex(0, 0);
    // curveVertex(0, 0);
    // endShape();
    noStroke();
    fill(255);
    ellipse(0, 0, this.rad * 2 * this.mass, this.rad * 2 * this.mass);
    pop();
  }
}